Please how do you model Heat Exchanger in Pipe Stress Analysis; what and what loads, do one consider

Your question is far too general to answer.

You could read the very many posts on this subject by using the 'search' facility.

You could also ask a stress engineeer in your company ?

check this web site....

http://www.whatispiping.com/

Thanks for your reply; what I mean is that do you limit the loading to the flanges or include the battery?

Hi,

Model the heat exchanger and limit the piping loads against the vendor allowables.
check the flange leakage also. If you have further doubts mail me
kbharani73@gmail.com.